Step 1: Install the SDK

You can install the SDK manually or via CocoaPods. The latter option is highly recommended.

Put these lines in Podfile:

target 'MyApp' do
  use_frameworks!

  pod 'FBSDKCoreKit'
  pod 'FBSDKLoginKit'
  pod 'FBSDKShareKit'
end

Run pod install in the terminal and open .xcworkspace instead of .xcodeproj afterwards.

FBSDKLoginKit and FBSDKShareKit are optional. You may or may not need them.

Step 2: Create an app on Facebook

Go to Quick Starts - Facebook for Developers to create an app.

Facebook will ask you to download the SDK after creating the app. You can skip this part if you installed the SDK via CocoaPods already.

Step 3: Edit .plist

1. To make your app able to “communicate” with Facebook, you need to put some settings in your .plist file. Facebook will give you the customized snippet on the Quick Starts page.
2. Edit your .plist file as source code.

1. Paste your customized snippet in the source code. Be careful! The snippet must be exactly the child of the <dict> tag. Your source code should be something like:

<plist version="1.0">
<dict>
    // ...
    //some default settings
    // ...
    <key>CFBundleURLTypes</key>
    <array>
        <dict>
            <key>CFBundleURLSchemes</key>
            <array>
                <string>fb{FBAppId}</string>
            </array>
        </dict>
    </array>
    <key>FacebookAppID</key>
    <string>{FBAppId}</string>
    <key>FacebookDisplayName</key>
    <string>{FBAppName}</string>
    <key>LSApplicationQueriesSchemes</key>
    <array>
        <string>fbapi</string>
        <string>fb-messenger-api</string>
        <string>fbauth2</string>
        <string>fbshareextension</string>
    </array>
<key>NSAppTransportSecurity</key>
<dict>
    <key>NSExceptionDomains</key>
    <dict>
        <key>facebook.com</key>
        <dict>
            <key>NSIncludesSubdomains</key>
            <true/>
            <key>NSExceptionRequiresForwardSecrecy</key>
            <false/>
        </dict>
        <key>fbcdn.net</key>
        <dict>
            <key>NSIncludesSubdomains</key>
            <true/>
            <key>NSExceptionRequiresForwardSecrecy</key>
            <false/>
        </dict>
        <key>akamaihd.net</key>
        <dict>
            <key>NSIncludesSubdomains</key>
            <true/>
            <key>NSExceptionRequiresForwardSecrecy</key>
            <false/>
        </dict>
    </dict>
</dict>
</plist>

If you paste the snippet at a wrong place, you will run into problems.

Step 4: Tell Facebook your bundle identifier on the Quick Starts page.

=> How to get bundle identifier

Step 5: Edit your AppDelegate.swift